Chip capacitor

ABSTRACT

An aluminum electrolytic chip capacitor having excellent resistance against vibrations is disclosed. The capacitor is free from breakage of soldered portions or lead wires due to the vibrations upon being mounted on a board. The capacitor includes a metal case accommodating a capacitor element and having its open end sealed with a sealing member, and an insulated terminal plate mounted on the case. The case is provided with an annular shrink portion at the sealing of the open end. The terminal plate includes a wall portion disposed at a position other than on a line of the lead wire bending direction of the periphery of the terminal plate. The wall portions cover at least the shrink portion. Inner surfaces of the wall portions abut the periphery of the case, thereby holding the case.

TECHNICAL FIELD

[0001] The present invention relates to a chip capacitor required tohave a large vibration resistance, and particularly to an aluminumelectrolytic chip capacitor to be mounted on a board as asurface-mounted capacitor.

BACKGROUND ART

[0002] FIGS. 16(a) and 16(b) are a front sectional view and a sidesectional view of a conventional aluminum electrolytic chip capacitor,respectively. Aluminum electrolytic chip capacitor 21 (hereinaftercalled capacitor 21) includes a capacitor element 23, a bottomedcylindrical metal case 24 in which the element 23 and electrolyte fordriving are accommodated, and a sealing member 25 for sealing the openend of case 24. The capacitor element 23 is formed by winding anode foiland cathode foil (not shown) with an anode lead wire 22 a and a cathodelead wire 22 b connected thereto, respectively, with a separatordisposed between them. A shrink portion 24 a is formed at sealing of thecase 24.

[0003] An insulated terminal plate 26 is disposed so as to abut the openend side of case 24, and its outer surface (a bottom of the figure) hasa hole 26 a and a grove portion 26 b. Through the hole 26 a, each of apair of lead wires 22 a and 22 b led out of capacitor element 23 passes,and in the grove portion 26 b, each of the lead wires 22 a, 22 b bentperpendicularly is placed. The bent portions of lead wires 22 a, 22 bare finished flat. In this manner, the capacitor 21 is mounted on asurface of a board (not shown).

[0004] After the conventional capacitor is mounted on the board, when astrong stress of vibration is applied thereto in Y directionperpendicular to X direction, i.e., the direction of connecting the leadwires 22 a and 22 b as shown in FIG. 17, the capacitor 21 vibrates likea pendulum since being connected to the board only at two portions ofthe lead wires 22 a and 22 b. Accordingly, soldered portions of the leadwires 22 a and 22 b connected to the board are peeled off, which maycause breakage of the lead wires.

[0005] Another conventional capacitor includes an insulated terminalplate of housing-like shape surrounding a capacitor body with lead wiresconnected thereto. In this technology, it is necessary to make the outerdiameter of the body substantially identical to the inner diameter of ahousing portion of the terminal plate in order to improve the vibrationresistance. Therefore, it is difficult to mount the capacitor body inthe housing portion.

[0006] Japanese Patent Laid-Open No. 9-162077 discloses a supportportion rises and extending from a periphery of an insulated terminalplate, and a projection disposed at the support portion which fits in ashrink groove portion of a capacitor. This document further discloses acapacitor including a support portion split by notches, and a capacitorincluding a cylindrical support portion made of resin having elasticityunitarily formed with an insulated terminal plate. These capacitors,since their support portions have annular shapes, have their capacitorbodies mounted. Since the support portions are formed only up to theshrink groove portions, these capacitors cannot stand sufficientlyagainst vibrations in consideration of mounting in, for example,automobiles.

[0007] As shown in FIG. 18, when being bent along the groove portion 26b disposed in the insulated terminal plate 26, the lead wires 22 a and22 b are bent at acute angles only at one portion of the hole 26 a.Therefore, the lead wires 22 a and 22 b, once being bent and placed inthe groove portion 26 b, tends to return to its original position due toa spring-back effect of the bent portion, and thereby generates a floatt. The float t lowers soldering strength when a thin solder is applied.

[0008] Further, as shown in FIG. 19, in a capacitor including a dummyterminal 28 disposed on the outer surface (soldering surface or bottomsurface) of the insulated terminal plate 27, the above problem isparticularly remarkable. In the worse case, the solder does not contactwith the dummy terminal 28. This may lead particularly to a seriousproblem since a thinner solder has been used recently.

[0009] In order to solve such problem, the lead wires 22 a are 22 b arebent with stronger forces, or the groove portion 27 a in the insulatedterminal plate 27 is formed deeper, thereby coping with the spring-backeffect. However, such measure may invite a problem that the lead wires22 a and 22 b cannot be soldered since remaining deep in the grooveportion 27 a.

DISCLOSURE OF THE INVENTION

[0010] An aluminum electrolytic chip capacitor is easily mounted, has anexcellent vibration resistance, and being soldered reliably even if alead wire is positioned deeply in a groove portion formed in aninsulated terminal plate.

[0011] The capacitor includes a capacitor element including a lead wirefor external leading, a metal case for accommodating the capacitorelement, a sealing member to seal an open end of the metal case, and aninsulated terminal plate disposed so as to abut the sealing member. Themetal case has a shrink portion of annular shape formed at the sealing.The capacitor further includes a wall portion disposed at other positionthan on a line in a lead wire bending direction of a periphery of theinsulated terminal plate. The wall portion is equal to or higher thanthe height of the shrink portion, and has its inner surface abut andhold the periphery of the metal case.

[0012] The capacitor, upon being mounted on a board, stands strongvibrations given in all directions including a direction crossing thelead wire bending direction, thereby assuring excellent reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a perspective view of an aluminum electrolytic chipcapacitor according to exemplary embodiment 1 of the present invention.

[0014]FIG. 2 is a perspective view of an insulated terminal plate of thecapacitor according to embodiment 1.

[0015] FIGS. 3(a) to 3(d) are plan views of another insulated terminalplates of the capacitor according to embodiment 1.

[0016]FIG. 4(a) is a sectional view of an aluminum electrolytic chipcapacitor according to exemplary embodiment 2 of the invention.

[0017]FIG. 4(b) is an enlarged view of an essential portion of acapacitor according to embodiment 2.

[0018]FIG. 5 is a bottom view of the capacitor according to embodiment2.

[0019]FIG. 6 is a perspective view of an insulated terminal plate of analuminum electrolytic chip capacitor according to exemplary embodiment 3of the invention.

[0020]FIG. 7 is a perspective view of an insulated terminal plate of analuminum electrolytic chip capacitor according to exemplary embodiment 4of the invention.

[0021] FIGS. 8(a) to 8(d) are plan views of another insulated terminalplates of the capacitor according to embodiment 4.

[0022]FIG. 9 is a sectional view of an aluminum electrolytic chipcapacitor according to exemplary embodiment 5 of the invention.

[0023]FIG. 10(a) is a perspective view of an insulated terminal plateprovided with a projection partially on an inner surface of a wallportion of the capacitor according to embodiment 5.

[0024]FIG. 10(b) is a perspective view of an insulated terminal plateprovided with a projection entirely on the inner surface of the wallportion of the capacitor according to embodiment 5.

[0025] FIGS. 11(a) and 11(b) are perspective views of an insulatedterminal plate of an aluminum electrolytic chip capacitor according toexemplary embodiment 6 of the invention.

[0026]FIG. 12 is an exploded perspective view of an insulated terminalplate of an aluminum electrolytic chip capacitor according to exemplaryembodiment 7 of the invention.

[0027]FIG. 13 is a perspective view of a holder of a capacitor accordingto exemplary embodiment 8 of the invention.

[0028]FIG. 14 is a bottom view of an aluminum electrolytic chipcapacitor according to exemplary embodiment 9 of the invention.

[0029]FIG. 15 is a sectional view of an aluminum electrolytic chipcapacitor for showing a test method according to exemplary embodiment 10of the invention.

[0030]FIG. 16(a) is a front sectional view of a conventional aluminumelectrolytic chip capacitor.

[0031]FIG. 16(b) is a side sectional view of the conventional capacitor.

[0032]FIG. 17 is a perspective view of an aluminum electrolytic chipcapacitor for showing a direction of vibrations given in a vibrationtest of an aluminum electrolytic chip capacitor.

[0033]FIG. 18 is a sectional view of an essential portion of theconventional capacitor for showing a lead wire floating.

[0034]FIG. 19 is a bottom view of a conventional aluminum electrolyticchip capacitor including a dummy terminal.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0035] (Embodiment 1)

[0036]FIG. 1 is a perspective view of an aluminum electrolytic chipcapacitor (hereinafter called capacitor) in exemplary embodiment 1 ofthe present invention. FIG. 2 is a perspective view of an insulatedterminal plate of the capacitor. FIGS. 3(a) to 3(d) are plan views ofanother insulated terminal plate. A metal case 1 accommodates acapacitor element together with electrolyte for driving. An open end ofthe case 1 is sealed with a sealing member (not shown). The capacitorelement is formed by winding anode foil and cathode foil with anode leadwire and cathode lead wire for external leading (not shown) connectedthereto, respectively, with a separator disposed between them. A shrinkportion la is formed by shrinking the case 1 at the sealing.

[0037] An insulated terminal plate 2 is disposed so as to abut thesealing member, and its outer surface (a bottom in the figure) has ahole 2 c through which each of a pair lead wire (not shown) led out ofthe capacitor element passes, and a grove portion 2 a in which the leadwire bent perpendicularly is placed. This configuration has thecapacitor mounted on a surface of a board. The lead wires are placed inthe groove portion 2 a so as to be substantially flush with the outersurface, and soldered as terminals when the capacitor is mounted on theboard.

[0038] A terminal plate 2 is shaped in square, and at its corners,plural wall portions 2 b having their inner surfaces abut and hold aperiphery of the case 1 are provided. The wall portion 2 b is higherthan a height covering the shrink portion 1 a, and the height ispreferably ½ or larger than the height of the metal case 1. The terminalplate 2 is unitarily formed with the wall portion made of insulatingresin so that a size between the inner surfaces of opposing wallportions 2 b is a little smaller than the outer diameter of the metalcase 1. This arrangement enables the terminal plate 2 to precisely holdthe periphery of the case 1, and therefore, suppresses excessivevibrations even when strong vibration is applied in a direction crossingthe lead wire bending direction to the capacitor mounted on a board.Accordingly, the capacitor assures excellent vibration resistance andhigh reliability.

[0039] Possible positions of the wall portions 2 b of the terminal plate2 are shown in FIGS. 3(a) to 3(d).

[0040]FIG. 3(a) shows a wall portion 2 b at the middle of each side ofthe square terminal plate 2. The four wall portions 2 b precisely holdthe case 1. A groove portion 2 a is formed on the surface opposite tothe wall portion 2 b in order to accommodate the lead wire. The leadwire passes through a hole 2 c.

[0041]FIG. 3(b) shows a wall portion 2 b at each corner of the squareterminal plate 2. The four wall portions 2 b precisely hold the case 1,and this arrangement improves strength of the wall portion 2 b byincreasing the thickness of the portion. If being too thick, the wallportion 2 b has reduced elasticity, and the metal case 1 cannot thus besmoothly fitted on the portion, thus making the capacitor element behardly mounted. However, as shown in FIG. 2, this problem can be solvedby a notch 2 d at the outer periphery of the wall portion 2 b.

[0042]FIG. 3(c) shows the wall portions 2 b at three portions in total,that is, at two corners which are ends of the lead wire bendingdirection of the square terminal plate 2 and at the middle of theopposite side. The three wall portions 2 b precisely hold the case 1.

[0043]FIG. 3(d) shows a pair of wall portions 2 b at positions otherthan on a line in the lead wire bending direction at the side of thesquare terminal plate 2. Even when strong vibration is applied in adirection crossing the lead wire bending direction, which is greatest indamage, the wall portions 2 b precisely hold the case 1.

[0044] (Embodiment 2)

[0045] FIGS. 4(a) and 4(b) are a front sectional view and an enlargedview of an essential portion of a capacitor according to exemplaryembodiment 2 of the present invention, respectively. FIG. 5 is a bottomview of it. The capacitor 3 includes a capacitor element 3 a, a bottomedcylindrical metal case 5 accommodating the element 3 a together withelectrolyte for driving, and sealing member 6 for sealing the open endof the case 5. The capacitor element 3 a is formed by winding anode foiland cathode foil (not shown) with anode lead wire 4 a and cathode leadwire 4 b connected thereto, respectively, with a separator disposedbetween them. Respective end portions (bent portions described later) ofthe anode lead wire 4 a and cathode lead wire 4 b are finished flat.

[0046] An insulated terminal plate 7 is disposed so as to abut the openend of metal case 5, and its outer surface (a bottom in the figure) hasa hole 7 a through which a pair of lead wires 4 a and 4 b led out of thecapacitor element 3 a passes, and a groove portion 7 b in which the leadwires 4 a and 4 b passing through the hole 7 a and bent perpendicularlyare placed. This arrangement allows the capacitor 3 to be mounted on aboard (not shown). A metal portion 7 c is disposed on the outer surfaceof the groove portion 7 b and on a part of the outer surface of terminalplate 7 connected to the portion. The metal portion 7 c may preferablybe made of a metal sheet or a metal-plated coat. The groove portion 7 bhaving the metal portion 7 c accommodates the lead wires 4 a and 4 bbent.

[0047] Even if the lead wires 4 a and 4 b are placed deeply in thegroove portion 7 b when the capacitor 3 is soldered and mounted on aboard, the solder contacts with the metal portion 7 c, thereby allowingthe capacitor 3 to be soldered. As a result, the lead wires 4 a and 4 bare securely soldered. The groove portion 7 b may be formed more deeplyin consideration of a spring-back effect of the lead wires 4 a and 4 b,and this suppress floating of the lead wires and improves theirsoldering reliability.

[0048] The metal portion 7 c may be disposed only on the outer surfaceof the groove portion 7 b, and may be formed on the outer surface of thegroove portion 7 b and a part of the outer surface of the terminal plate7 connected to the portion 7 b. The portion 7 c may be made of ametal-plated coat or a metal sheet according to, for example, a shapeand size of the terminal plate 7 or a cost.

[0049] The terminal plate 7 is provided with chamfered portions 7 d atits two corners which are located on one of sides crossing the directionof the groove portion 7 b. Predetermining that either one of the anodelead wire 4 a and cathode lead wire 4 b at the side where the chamferedportion 7 d is disposed allows anode and cathode to be identified froman appearance of the capacitor 3 mounted.

[0050] (Embodiment 3)

[0051]FIG. 6 is a perspective view of an insulated terminal plate of acapacitor according to exemplary embodiment 3 of the present invention.Similarly to embodiment 1, insulated terminal plate 8 has a hole 8 dthrough which a pair of lead wires (not shown) led out of a capacitorelement pass, and a groove portion 8 a in which the lead wires bentperpendicularly are placed. And at its corners, plural wall portions 8 band 8 c having respective inner surfaces abut and hold the periphery ofa metal case. Notch 8 e is formed at each outer periphery of wallportions 8 b and 8 c. The wall portions 8 b and 8 c are disposed eachfor two, and they have different heights H1 and H2. Predetermining thateither one of an anode and cathode of the lead wires are located ateither one of the wall portions 8 b and 8 c having different heightsallows the anode and cathode to be identified from an appearance of thecapacitor mounted.

[0052] The capacitor according to embodiment 3 assures excellentvibration resistance and reliability similarly to embodiment 1.

[0053] (Embodiment 4)

[0054]FIG. 7 is a perspective view of an insulated terminal plate of acapacitor according to exemplary embodiment 4 of the present invention.FIGS. 8(a) to 8(d) are plan views of another insulated terminal plate.Similarly to embodiment 1, an insulated terminal plate 9 has holes 9 cthrough which a pair of lead wires (not shown) led out of a capacitorelement pass, a groove portion 9 a in which the lead wires bentperpendicularly are placed. And at its corners, plural wall portions 9 bhaving respective inner surfaces abut and hold the periphery of a metalcase. Notch 9 d is disposed at each outer periphery of the wall portions9 b. The terminal plate 9 is finished square, and chamfered portion 9 eis disposed at two corners, either end of one of the sides crossing adirection of the groove portion 9 a. Predetermining that either one ofan anode and cathode of the lead wires at a side where the chamferedportion 9 e is disposed allows the anode and cathode to be identifiedfrom an appearance of the capacitor mounted.

[0055] The wall portions 9 b may be positioned at various positions,similarly to embodiment 1. The positions are shown in FIGS. 8(a) to8(d). Terminal plate 9 shown in FIGS. 8(a) to 8(d) provides the sameeffect as the terminal plate according to embodiment 1, and the detaileddescription is omitted.

[0056] Combining the terminal plate according to embodiment 4 with thewall portions having different heights according to embodiment 3enhances the effects of the terminal plate.

[0057] (Embodiment 5)

[0058]FIG. 9 is a sectional view of an insulated terminal plate of acapacitor according to exemplary embodiment 5 of the present invention.FIGS. 10(a) and 10(b) are perspective views of a terminal plate. A metalcase 1 of the capacitor is provided with a shrink portion 1 a. A leadwire 1 b is led out of a capacitor element (not shown) in the case 1.Similarly to embodiment 1, an insulated terminal plate 10 has a hole 10c through which lead wires 1 b (and 1 c, not shown) led out of thecapacitor element passes and a groove portion 10 a in which the leadwire 1 b bent perpendicularly is placed. And at its corners, plural wallportions 10 b having respective inner surfaces abut and hold a peripheryof the case 1. Notch 10 d is disposed at the outer periphery of the wallportion 10 b.

[0059] The inner surface of wall portion 10 b is provided with aprojection 10 e. FIG. 10(a) shows the projection 10 e disposed partiallyon the inner surface of the wall portion 10 b, and FIG. 10(b) shows theprojection 10 e disposed entirely on the inner surface of the wallportion 10 b. The projection 10 e fits into the shrink portion 1 a ofthe metal case 1, as shown in FIG. 9, and the wall portion 10 bsubstantially reaches a middle area of the case 1 beyond the projection10 e, thereby holding the case 1. This arrangement provides thecapacitor with higher vibration resistance since an area contacting withthe case 1 increases. Further, the wall portion 10 b securely holds thecase 1 against vertical vibrations as well, and thus suppressesgenerating excessive vibrations. The projection 10 e is preferablyformed unitarily with the wall portion 10 b made of resin, or may bemade of an elastic material, such as an individual piece of rubber.

[0060] (Embodiment 6)

[0061] FIGS. 11(a) and 11(b) are perspective views of an insulatedterminal plate of a capacitor according to exemplary embodiment 6 of thepresent invention. Similarly to embodiment 1, an insulated terminalplate 11 has holes 11 c through which a pair of lead wires (not shown)led out of a capacitor element pass and a groove portion 11 a in whichthe lead wires bent perpendicularly are placed. And at its corners,plural wall portions 11 b having respective inner surfaces abut and holdthe periphery of a metal case.

[0062] In embodiment 6, the wall portion lib is made of elastic metal,and a projection 11 d is disposed on the inner surface of the portion 11b. The wall portions 11 b which are individually formed are integrallyformed when the terminal plate 11 is formed. Or, the wall portion 11 bis preferable to be press-fitted and secured in a recess disposed in theterminal plate 11.

[0063] The projection 11 d on the inner surface of wall portion 11 b ispreferably formed after fitting to the terminal plate 11 in the metalcase 1.

[0064] The above configuration allows the wall portion 11 b to hold themetal case 1 more reliably, thus providing higher vibration resistance,and suppressing generating excessive vibrations including verticalvibrations.

[0065] In embodiment 6, the projection 11 d is disposed on the innersurface of the wall portion 11 b, but similar effects are obtainableeven if the wall portion 11 b does not have the projection 11 d.

[0066] Further, bonding the wall portions to the periphery of the metalcase with adhesive allows the capacitor to be held more reliably in eachof embodiments 1 to 6.

[0067] (Embodiment 7)

[0068]FIG. 12 is an exploded perspective view of a capacitor accordingto exemplary embodiment 7 of the present invention. A metal case 1 ofthe capacitor is provided with a shrink portion 1 a. Similarly toembodiment 1, an insulated terminal plate 12 has a hole (not shown)through which a lead wire led out of a capacitor element passes and agroove portion 12 a in which the lead wire bent perpendicularly isplaced. And at its corners, plural wall portions 12 b having respectiveinner surfaces abut and hold the periphery of the case 1. Notch 12 c isdisposed at the outer periphery of the wall portion 12 b.

[0069] An annular holder 13 is tapered to have its lower end side besmaller than a distance between the inner surfaces of the wall portions12 b opposing to each other, and its upper end side be greater than thedistance. The taper allows the holder 13 to fit onto the case 1. Theholder 13 securely holds the case 1 with entire inner surfaces of thewall portions 12 b. This arrangement suppresses generating excessivevibrations and provides the capacitor with higher vibration resistance.The holder 13 may be made of resin or metal. The holder 13 may not havethe annular shape unitarily formed, but may be a wedge-like piecedisposed only at each wall portion 12 b.

[0070] (Embodiment 8)

[0071]FIG. 13 is a perspective view of a holder of a capacitor accordingto exemplary embodiment 8 of the present invention. In embodiment 8, theholder is that of embodiment 7 provided with plural slits at its upperend side. The other portion than the slits is identical to embodiment 7,and therefore, the description is omitted for the identical portion, andonly different portions are described below.

[0072] An annular holder 14 is tapered to have its lower end side besmaller than a distance between the inner surfaces of wall portionsopposing to each other, and have its upper end side be greater than thedistance. The upper end side is provided with plural slits 14 a. Thus,the upper end side provided with the slits 14 a widens in a direction ofits outer periphery and has a larger diameter. This allows the holder 14to fit onto a metal case 1. In addition, the upper end side of theholder fitting onto the case is narrowed in a direction of its innerperiphery by the wall portions on an insulated terminal plate, and has asmaller diameter. The holder securely holds the periphery of the metalcase with its entire inner surface, and thus suppresses generatingexcessive vibrations to ensure high vibration resistance.

[0073] (Embodiment 9)

[0074]FIG. 14 is a bottom view of a capacitor according to exemplaryembodiment 9 of the present invention. Similarly to embodiment 1, aninsulated terminal plate 15 has holes 15 c through which a pair of leadwires 1 b and 1 c led out of a capacitor element pass and a grooveportion 15 a in which the lead wires 1 b and 1 c bent perpendicularlyare placed. At its corners, plural wall portions 15 b abut and hold aninner periphery of a metal case 1.

[0075] A pair of dummy terminals 15 d at the bottom of the terminalplate 15 are located at positions other than on a line in a bendingdirection of the lead wires 1 b and 1 c of the periphery of the terminalplate 15. The terminals 15 d are soldered when the capacitor is mountedon a board similarly to the lead wires 1 b and 1 c. This arrangementallows the insulated terminal plate 15 to be mounted on a board, andthus suppresses generating excessive vibrations to obtain excellentvibration resistance.

[0076] (Embodiment 10)

[0077] Capacitors according to some of the embodiments of the presentinvention and conventional capacitors (φ18×16.5 mmL) as comparativeexamples were manufactured five pieces each. The capacitors were mountedon a board for vibration tests, and the results of the tests are shownin Table 1.

[0078] (Samples)

[0079] (a) A capacitor including an insulated terminal plate having wallportions in a middle of each side of the terminal plate as shown in FIG.3(a) of embodiment 1;

[0080] (b) A capacitor including an insulated terminal plate having wallportions at each corner of the terminal plate as shown in FIG. 3(b) ofembodiment 1;

[0081] (c) A capacitor including an insulated terminal plate having ametal plate on an outer surface of a groove portion as shown in FIG. 4of embodiment 2;

[0082] (d) A capacitor including an insulated terminal plate having aprojection disposed partially on sample (b) as shown in FIG. 10(a) ofembodiment 4;

[0083] (e) A capacitor including an insulated terminal plate having aprojection disposed entirely on sample (b) as shown in FIG. 10(b) ofembodiment 4;

[0084] (f) A capacitor including an insulated terminal plate haivng aprojection disposed entirely on sample (a);

[0085] (g) A capacitor including an insulated terminal plate having wallportions made of elastic metal having projections as shown in FIG. 11(a)of embodiment 5;

[0086] (h) A capacitor including an annular holder disposed between ametal case and a wall portion as shown in FIG. 12 of embodiment 6; and

[0087] (i) A conventional capacitor.

[0088] (Test conditions)

[0089] (1) The number of capacitors having their lead wires broken:

[0090] Direction of Vibrations: X-, Y-, and Z-directions as shown inFIG. 15.

[0091] Amplitude of Vibrations: 7.5 mm

[0092] Acceleration of Vibrations:30G

[0093] Frequency of Vibration: 5-1000 Hz

[0094] Time for Vibration: 15 cycles, total 120 min. (8 min. per cycle).

[0095] (2) Peak Vibration

[0096] Direction of Vibration: Y-direction shown in FIG. 15.

[0097] Acceleration of Vibration: 1G

[0098] Frequency of Vibration: 5-1000 Hz

[0099] Time for Vibration: 8 min. TABLE 1 Samples (a) (b) (c) (d) (e)(f) (g) (h) (i) Number of X- 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5Capacitors direction Having Lead Y- 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 5/5Wires Broken direction Z- 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 directionAcceleration of Peak 2.5 2.4 2.2 2.4 2.3 2.2 2.4 2.2 5.5 Vibration (G)

[0100] As shown in above, all the capacitors of the present inventionexhibited reliable vibration resistance without breakage of the leadwires. Also, the capacitors of the present invention accepted the peakacceleration less than one half of that on the conventional capacitor.

[0101] Further, a dummy terminal 15 d shown in FIG. 14 of embodiment 9was made on samples (a), (b), and (c) for a test of the capacitors, andthe results of the test are shown in Table 2.

[0102] (Test conditions)

[0103] (1) Acceleration of Peak Vibration

[0104] Direction of Vibration: Y-direction shown in FIG. 15.

[0105] Acceleration of Vibration: 1G

[0106] Frequency of Vibration: 5-1000 Hz

[0107] Time for Vibration: 8 min.

[0108] (2) Breaking strength

[0109] As shown in FIG. 15, the insulated terminal plate 2 fitting tothe metal case 1 is pressed in a Y-direction. The soldered portionindicates the pressure applied at the breakage. TABLE 2 Samples (a) (b)(i) Dummy Yes No Yes No Yes No Terminal Peak 2.5 2.5 2.5 2.4 5.4 5.5Acceleration (G) Applied Pressure 10.2-11.3 6.6-7.0 9.5-11.8 6.4-7.19.8-11.2 6.5-7.1 (kg)

[0110] As is apparent in above, the dummy terminal 15 d does not lowerthe acceleration of vibration, and however, increases the breakingpressure. The terminal increases its soldering strength, and allows acapacitor to have its soldered portions be hardly broken or peeled dueto vibrations.

[0111] According to the above embodiments, the technology of the presentinvention is applied to an aluminum electrolytic chip capacitor, but isnot limited to this. It is applicable to an electronic chip component,such as a chip capacitor having a similar shape.

INDUSTRIAL APPLICABILITY

[0112] The present invention relates to a chip capacitor, particularlyto an aluminum electrolytic chip capacitor to be mounted on a board andrequired to have excellent vibration resistance.

[0113] The capacitor includes an insulated terminal plate having wallportions which abut and hold a metal case. The capacitor ensuringexcellent vibration resistance even against strong vibrations applied inall directions, and thus being reliable.

[0114] The capacitor may include a metal portion made of metal-platedcoat or a metal sheet on a surface of a groove portion of the insulatedterminal plate. The capacitor allows the metallic portion to be solderedeven when lead wires are placed deeply in the groove portion, and as aresult, the lead wires are soldered reliably as well.

1. A chip capacitor comprising: a capacitor element having an anode leadwire and a cathode lead wire connected thereto; a cylindrical metal caseaccommodating said capacitor element, said metal case having a bottomand having an annular shrink portion formed thereon; a sealing memberfor sealing an open end of said metal case, said sealing member havingholes formed therein through which said anode lead wire and said cathodelead wire pass, respectively; an insulated terminal plate disposed so asto abut said sealing member, said insulated terminal plate having holesformed therein through which said anode lead wire and said cathode leadwire pass, respectively, and a groove portion formed on outer surfacethereof in which said anode lead wire and said cathode lead wire arebent and placed; and a plurality of wall portions disposed on aperiphery of said insulated terminal plate at respective positions on aline other than a line in a bending direction of said anode and cathodelead wires, said plurality of wall portions abutting a periphery of saidmetal case at least up to said shrink portion.
 2. The chip capacitor ofclaim 1, wherein said insulated terminal plate is shaped in square, andwherein said plurality of wall portions are disposed at middles of sidesof said insulated terminal plate, respectively.
 3. The chip capacitor ofclaim 1, wherein said insulated terminal plate is shaped in square, andwherein said plurality of wall portions are disposed at corners of saidinsulated terminal plate, respectively.
 4. The chip capacitor of claim1, wherein said insulated terminal plate is shaped in square, andwherein said plurality of wall portions are disposed at corners at endsof a first side extending in said bending direction of said lead wires,respectively, and at a middle of a side opposing to said first side. 5.The chip capacitor of claim 1, further comprising: a metal portiondisposed on a surface of said groove portion.
 6. The chip capacitor ofclaim 5, wherein said metal portion is made of one of metal-plated coatand a metal sheet.
 7. The chip capacitor of claim 1, further comprising:a metal portion disposed on a surface of said groove portion and on apart of a surface of said insulated terminal plate connecting to saidsurface of said groove portion.
 8. The chip capacitor of claim 7,wherein said metal portion is made of one of metal-plated coat and ametal sheet.
 9. The chip capacitor of claim 1, wherein a wall portion ofsaid plurality of wall portions close to said anode lead wire has adifferent height than a wall portion of said plurality of wall portionsdisposed close to said cathode lead wire.
 10. The chip capacitor ofclaim 1, said insulated terminal plate has two corners chamfered, saidcorners being located on one of sides of said anode lead wire and saidcathode lead wire.
 11. The chip capacitor of claim 1, furthercomprising: projections disposed on said plurality of wall portions,respectively, said projections fitting on said shrink portion.
 12. Thechip capacitor of claim 11, wherein said plurality of wall portions ismade of elastic metal.
 13. The chip capacitor of claim 1, wherein saidplurality of wall portions are bonded to said periphery of said metalcase.
 14. The chip capacitor of claim 13, wherein said plurality of wallportions are bonded to said periphery of said metal case with adhesive.15. The chip capacitor of claim 1, further comprising: a holder havingan annular shape disposed between said metal case and said plurality ofwall portions.
 16. The chip capacitor of claim 15, wherein said holderhas a plurality of slits formed in one end thereof.
 17. The chipcapacitor of claim 1, further comprising: a pair of dummy terminalsdisposed on said insulated terminal plate and located on a line otherthan a line in said bending direction of said lead wires.